What is the benefit of getting *high reputation score* in this web site?

The reputation score system is really more about the low rep score. When you have questions, comments, and answers that are removed, your rep goes down. If your rep falls below -60, then you cannot post anymore. It's a good system to keep out spammers.

When someone presses the up arrow to vote up one of your questions or answers, your rep goes up by 5. When someone presses the down arrow, it goes down by 2. If your post gets removed, your rep drops by 20. You need a rep of -59 or higher to post on this site, if it drops below that you can't do anything.

Oh another benefit is if you have at least 10 rep, you can report a question, comment, or answer as being abusive, and it will be reviewed. If a certain number of members report the same post, it's removed automatically. It's not an exact number though. The higher the rep each user has, the less users it takes for a post to get deleted.

I personally have the highest rep on the site at a whopping 482. I'm damned proud :P

I believe the second highest rep is figment at 95: http://www.ehelp.com/profiles/1363911579/figment